Then either use the wizard "File > New > Other > Acceleo > Acceleo Module File" and make sure you select "create service wrapper" in the combo box "initialize contents". Select the Java file containing the method above and you'll get a new Acceleo module with the query corresponding to that java service (or watch the step by step http://www.obeonetwork.com/page/the-acceleo-queries).

You'll then be able to call that service from your module (example if you've called the Acceleo module containing the service "acceleo::service::StereotypeUtils") :